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Meclonazepam

Meclonazepam molecule structureMeclonazepam molecule structure
Chemical Class
1,4-Benzodiazepine

Meclonazepam is a benzodiazepine derivative structurally related to clonazepam, first developed by Hoffmann-La Roche during the 1960s. It was initially investigated for potential antiparasitic applications, particularly in the treatment of schistosomiasis. Although it has appeared on the grey market as a recreational depressant, it has not achieved widespread use. As with other benzodiazepines, meclonazepam is considered habit-forming and carries the risk of physical dependence with repeated administration.

Dosage & Duration

Dosage

Doses are population estimates that vary widely between individuals.

Moderate3-6 mg
Heavy6+ mg

Duration

Onset20-60 minutes
After Effects1-6 hours
Total9-15 hours

Subjective Effects

Legacy content. A statistically backed ontology from Mindstate Design Labs is coming soon.

The experience is that of a classical benzodiazepine, dominated by sedation, anxiety relief, and physical relaxation rather than any notable sensory alteration. At sufficient doses the compound acts as a hypnotic, pulling the user toward sleep, and recall of the period after ingestion may become patchy or absent.

Physical

The body feels heavy, relaxed, and sedated, with pronounced muscle relaxation and impaired coordination that can make walking or fine motor tasks difficult.

Sedation

Cognitive

The headspace is defined by suppression: anxiety fades into a calm, tranquil state, while memory formation becomes unreliable at higher doses.

Suppressions

Reagent Testing

Expected colorimetric results for common reagent tests. Colors show reaction change over 1–2 minutes.

Marquis(MQ)
No reaction
No reaction
Mecke(ME)
No reaction
No reaction
Mandelin(MD)
No reaction
No reaction
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Pharmacology

Pharmacodynamics

Meclonazepam produces its sedative and anxiolytic effects through modulation of the GABA-A receptor, consistent with the mechanism shared by other benzodiazepine compounds. It acts as a positive allosteric modulator at the benzodiazepine binding site of the GABA-A receptor.

Pharmacokinetics

Absorption & half-lifenot documented yetMetabolitesnone documented yet

Interactions

Interactions not written up yet

An unlisted combination is an unknown one, not a safe one. Check a dedicated combination chart before mixing.

Check TripSit

Tolerance

Tolerance timelines are rules of thumb, not exact schedules, and vary widely between individuals and use patterns.

Cross Tolerance

Benzodiazepines, Other GABA-A receptor positive allosteric modulators

Harm Potential

Addiction & Dependence

Psychological

Categorized as habit-forming with recognized potential for recreational use due to its sedative and anxiolytic effects.

History & Culture

Meclonazepam was first synthesized by a research team at Hoffmann-La Roche during the 1970s as a benzodiazepine derivative structurally related to clonazepam. Early investigations identified potential anti-parasitic applications against Schistosoma mansoni, the parasitic flatworm responsible for…

Legality

By Country

Illegal1
United Kingdom flagUnited KingdomIllegal

References

Citations

  1. Misuse of Drugs Act 1971 — Schedule 2: Controlled Drugs (latest available revised version). legislation.gov.uk (n.d.). https://www.legislation.gov.uk/ukpga/1971/38/schedule/21
  2. The Misuse of Drugs Act 1971 (Amendment) Order 2017 — article 5. legislation.gov.uk (n.d.). https://www.legislation.gov.uk/uksi/2017/634/article/5/made1
  3. The Misuse of Drugs Act 1971 (Amendment) Order 2017 — article 1. legislation.gov.uk (n.d.). https://www.legislation.gov.uk/uksi/2017/634/article/1/made1
  4. The Misuse of Drugs Regulations 2001 — Schedule 1 (latest available revised version). legislation.gov.uk (n.d.). https://www.legislation.gov.uk/uksi/2001/3998/schedule/11
  5. The Misuse of Drugs (Amendment) Regulations (Northern Ireland) 2018 (S.R. 2018/4). legislation.gov.uk (n.d.). https://www.legislation.gov.uk/nisr/2018/4/made1
  6. Misuse of Drugs Act 1971 — section 5: Restriction of possession of controlled drugs. legislation.gov.uk (n.d.). https://www.legislation.gov.uk/ukpga/1971/38/section/51

Article Status

  • Josie Kins avatar
    Step 1 · Automated synthesis

    An autonomous workflow built by Josie Kins compiled this article's foundation from information published across the web.

  • Step 2 · First-pass reviewPending

    Not yet reviewed — this article is pending editorial review by Lyrea.

  • Step 3 · Citation reviewPending

    No one has reviewed this article's citations yet. That second pass checks each claim against the source it cites.

Recent changes7 human edits · latest

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24 January 2026

  1. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  2. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  3. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  4. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  5. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  6. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  7. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

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